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RTK Base Station Setup
OUO6050,000227B –19–14NOV06–1/2
PDOP Definition
PC9548 –UN–06NOV06
A—Horizontal Precision (m) B—Maximum PDOP Value
The Position Dilution of Precision (PDOP) is likely one
of the most critical GPS AutoTrac values to monitor.
As the PDOP value increases, both the horizontal and
vertical precision (guidance accuracy) of your data
points decreases.
To help illustrate this relationship, please review the
graph, which plots the PDOP value against the
horizontal precision points collected on and around the
University of Montana campus. Ten locations were
collected to serve as ground control points to register
an April 4, 1999 aerial photograph of the University
area. You can see that as the PDOP value climbs from
a minimum of 1.15 to a maximum of approximately
4.5, the horizontal precision and accuracy decreases
from about 1.15 meters to about 1.9 meters. PDOP
values below 7 are generally required to collect data at
a 1 meter accuracy range (as determined by the
PDOP mask set on your data logger) and any value
below 3.5 is considered in-range for AutoTrac
applications.
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